Here is the full list of all 41 Castle on the Coast achievements.
DETONATE your save file.
Activate the hidden player 2 camera mode
Turn on co-op mode
Bounce off a character 30 times
Bounce off a character 10 times
Spin a character 30 times
Spin a character 10 times
Cheerfully wave 30 times
Take down 15 suites of armor
Defeat 20 of your bretheren in wood
Customize your appearance while wearing the kid costume
Reach the top of the distant, ocean tower
Drive a submarine into the library?
Reach the peak of one of the large, distant mountains on the mainland
Escape the confines of the playable castle area
Drive a car into the library
Reach the highest point of the castle. Wow!
Play the world's largest musical instrument
Unlock all costumes
Unlock the secret costume
Discover the secret ocean
Beat the game!
Obtain the ocean's keystone
Obtain the stunt park's keystone
Unlock Vendrick's costume
Unlock Aleandra's costume
Defeate Aleandra and obtain the forest keystone
Collect every star
Collect every moon star
Unlock your first costume
Unlock the mecha costume
Defeate Vendrick and obtain the rainy cathedral keystone
Accumulate 1,000 unspent petals
Survive an alternate dimension
Collect every orb star
Find a hidden ball
Collect every spiky star
Unlock the jetpack
Arrive at the Castle on the Coast
Taste defeat for the first time.
Make friends with a shark, awwwww...